August 28, 2013
The San Luis Obispo County Board of Supervisors have adopted an urgency ordinance this week that that prohibits new development or the planting of crops in the Paso Robles Groundwater Basin area unless water use can be offset on a 1-1 ratio. All four sitting supervisors agreed to the plan surprising some observers. The measure required all four agree to be implemented.
The ordinance comes as the Paso Robles area has experienced a drastic drop in groundwater levels of as much as 70 feet or more in the past 16 years (see map).Critics blame the big increase in grape vineyards in the region over the years and of course the drought.
Some areas like San Miguel and Shandon were not included – areas where the drop in water level has not be so severe. The measure is in place for only 45 days and then supervisors can extend it for up to two years.
The ordinance requires the metering of new irrigation wells that will be monitored by the county.
Supervisors have vowed to look at all ways to help the Basin including Conservation -Supplemental Water and Recycled Water as well as Basin Management
Based on suggestions from a Blue Ribbon Task Force outlined in May a feasibility study will also look at tapping supplemental sources of water.
That includes water from Nacimiento Lake as well as State Water Project supplies that the county has a right to tap but over the years has chosen not to.
The supervisors- wearing their San Luis Obispo County Flood Control and Water Conservation District hat – on Aug 16 authorized a release of request for qualifications to prepare several feasibility studies.
One would look to analyze options for using water that may be available in the Salinas River Watershed, Salinas Reservoir and Nacimiento Reservoir to offset pumping and stabilize groundwater levels in the Paso Robles Groundwater Basin .
Some option here are:
– Capturing, diverting and/or detaining an estimated 10,000 – 12,000 AFY average annual spill over the dam at various locations
– Exchanging available Nacimiento water for additional Salinas Reservoir releases via cooperative agreement
Additional recharge of the Salinas River or main Basin with Nacimiento Water
There is 6,095 AFY unsubscribed and available for purchase.
A second supplemental source is State Water Project water where up 15,273 AFY is available.
In 1963 SLO County contracted for 25,000 acre ft per year of State Water delivered by pipeline from the California Aqueduct in the SJ Valley near Kettleman City. Only about 8487 acre ft is delivered leaving an excess allotment. The State Water Projects’ Coastal Branch Aqueduct was completed in 1997 to serve San Luis Obispo and Santa Barbara counties.
But in SLO County only some area take State Water and Paso Robles is not one of them.Bringing in State Water could encourage the wine growers not to pump groundwater helping the Basin recover – or so goes the argument.
Supervisors will look to expert consultants to advise them about tapping these supplemental sources, the costs and timelines, pluses and minuses.
Back in 2006 the county considered using State Water to recharge Paso Robles groundwater but decided at the time the pipe infrastructure was too expensive.
A Tribune story back then mentions a key reason why SLO County has not committed to the water – fear of growth.” The county signed up with the state in 1963 for 25,000 acre-feet of water a year, but cities and other local water agencies, some leery of possible growth and worried about the cost, only reserved about 8,500 acre-feet of that. An acre-foot of water serves two to three homes for a year in the hot North County and four to five homes on the cooler coast.”
But after several years of drought and the promise of more dry years -could there be a change of heart? It sound like some months before we get some answers and consultants are ready to start their work on these studies.
Some argue that these are potential “long term” solutions and the Basin might not see this water for many years. That’s what they said back in 2006.

It should be noted at all major ag counties in California supplement their hometown water with imported water from the rainier parts of the state. For this benefit ag is asked to be a major player in footing the bill.